Photonics Convergence to Underpin Industry 4.0

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The smart factory. The fourth industrial revolution. The industrial internet. Whatever you prefer to call it, Industry 4.0 is becoming one of the defining themes of the current era, promising the combination of connectivity, flexibility, artificial intelligence and speed required to deliver next-level industrial productivity.

So where does photonics fit in? Perhaps it would be easier to ask where doesn’t photonics fit in. From high-speed optical data links to the versatility of laser materials processing, and the feedback and intelligent decision-making made possible by machine vision systems and optical sensors, the smart factories of the near future will exploit photonics like none before.

At the Optoelectronics Research Centre (ORC) in at the University of Southampton in the UK, and through the Engineering and Physical Sciences Research Council (EPSRC)-funded Future Photonics Manufacturing Hub, we’re developing many of the technologies that will enable that transformation: optical fibres for ultrahigh-speed, reliable data communication; fibre lasers that will perform much of the manufacturing in future factories; sensors for intelligent feedback; even optical systems that change dynamically according to the particular manufacturing task at hand.

One of our key technologies is hollow-core (HC), or “holey” fibre. Professor David Richardson explains that this impacts both high-power fibre laser delivery and communications, lending the ability to transfer unprecedented power from the laser to the distant workpiece, and optical network connectivity on the petabit-per-second scale with extremely low latency for real-time feedback and control in the factory.

Thanks to recent progress made under another EPSRC grant, we can now produce advanced HC fibres in lengths exceeding tens of kilometres with excellent uniformity and minimal light-glass interaction. Advances include the ability to intelligently design HC fibres from the starting preform with much-improved predictability, thanks to fluid dynamics modelling – enabling, for example, new anti-resonant fibres that offer the possibility of simultaneous communication via multiple wavelength bands.

“Making better fibres means more data, more power, more dimensionality, better environmental protection,” says Richardson. “We are adding to the armoury of optics for Industry 4.0.”

Part of that armoury is the possibility of low-cost, short-reach HC fibres for data-center-like connectivity in the factory with extremely low latency for real-time feedback and control. “Early studies have shown that the latency advantage is real,” he adds.

Smart lasers

With much-improved advanced fibre production capability now available, Richardson and others at the ORC have just begun a £6 million follow-up effort. Also funded by the EPSRC, the programme will see the technology developed for applications ranging from cutting-edge science to medical imaging and factories of the future.

On one level this will support pumping higher-power beams for laser materials processing, but with the likes of BT and Microsoft among the industry partners, communications will clearly be a major element. Richardson says that the reduced light-matter interactions enabled by transmitting light through the air of the hollow core – rather than through glass – will result in the kind of latency and optical losses needed for what’s envisaged as the ‘tactile’ internet, facilitating real-time wireless human control of real and virtual objects. Other possibilities include using adapted HC fibres to double up as gas sensors and data carriers.

Richardson’s colleague Professor Michalis N. Zervas (shown has already explored ways to double the typical output of a fibre laser, and is now working on approaches to control output to an unprecedented degree: for the smart factory, enter the “smart laser” and “smart photon pipes”.

“A smart laser looks like an electronic equivalent – a single, small-sealed, maintenance-free enclosure with a fully controlled output that is responsive to changes in the workpiece,” Zervas explains. “The laser knows what material it is processing, how the process is developing and when it is finished. It is able to adapt to changes in the materials, their shape, reflectivity, thickness and orientation.”

Adaptive beam shaping

Another approach to “smart laser” manufacturing is being pursued by ORC research fellow Dr Ben Mills. Using Digital Micromirror Devices (DMDs) developed by Texas Instruments, he is looking to combine the precision manufacturing capability of femtosecond lasers with high-speed control of beam-shape – potentially enabling some extraordinary applications across multiple sectors.

“We’re using high-speed, high-precision beam shaping to unlock a revolution in laser processing; for applications ranging from sensing to healthcare,” says Mills of the highly-customisable technology.

Capable of switching between conventional Gaussian, square, pyramidal or, indeed, any desired beam shape, the latest closed-loop system self-corrects in real-time, for example to work around a speck of dust in the laser processing zone – putting it clearly in the realm of Industry 4.0. What Mills describes as “on-the-fly, intelligent, adaptive laser processing” can be achieved with a high-speed camera looking along the beam line to provide feedback. Although the team is using a pulse repetition rate of only 10 Hz in current proof-of-principle experiments, Mills points out that beam shaping will ultimately be possible at much more industry-relevant rates of up to 30 kHz.

The potential for industrial applications of dynamic beam-shaping of femtosecond laser pulses is significant – the resultant multiphoton absorption enables material processing in almost any material, at extremely high precision. The current challenge for the team is to move to 3D manufacturing using this beam-shaping approach.

“We are investigating a range of both additive and subtractive laser-based processes,” Mills says. “We believe our approaches will eventually enable the fabrication of 3D structures from almost any material, at a resolution of hundreds of nanometres.”

Photonics convergence

Looking to 2020 and beyond, it is clear that lasers and photonics will be pivotal to delivering Industry 4.0 on multiple fronts. ORC director Professor Sir David Payne, a keynote speaker at this year’s CLEO Europe conference in Munich, summarises:

“We are entering an unprecedented era of convergence in photonics innovation. Progress conceived for one application, for example lasers or silicon photonics, will be rapidly re-deployed across all society’s major challenges – from individualised manufacturing, to healthcare and autonomous vehicles.”

That means digital tuning of fibre laser pulses for each manufacturing process, optimising productivity and flexibility in cutting, joining and marking applications. Simultaneously, HC optical fibre will enable flexible delivery of that light to the workpiece, coupled with real-time, low-latency ultrahigh-bandwidth connectivity of machines and factories, removing lag in digital process control.

“The convergence of processing and communications photonics in the hardware underpinning Industry 4.0 is stimulating demand for more integration and new approaches to manufacturing photonics components,” Payne adds. “This will drive new industrial partnerships, multiplying our impact and unlocking further economic growth.”